package cn.enjoy.javaapi;

import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;

import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Created by VULCAN on 2018/11/7.
 */
public class ZooKeeperWatcher implements Watcher  {

    /** 定义原子变量 */
    AtomicInteger seq = new AtomicInteger();
    /** 定义session失效时间 */
    private static final int SESSION_TIMEOUT = 10000;
    /** zookeeper服务器地址 */
    private static final String CONNECTION_ADDR = "192.168.198.130:2181";
    /** zk父路径设置 */
    private static final String PARENT_PATH = "/testWatch";
    /** zk子路径设置 */
    private static final String CHILDREN_PATH = "/testWatch/children";
    /** 进入标识 */
    private static final String LOG_PREFIX_OF_MAIN = "【Main】";
    /** zk变量 */
    private ZooKeeper zk = null;
    /** 信号量设置，用于等待zookeeper连接建立之后 通知阻塞程序继续向下执行 */
    private CountDownLatch connectedSemaphore = new CountDownLatch(1);

    /**
     * 创建ZK连接
     * @param connectAddr ZK服务器地址列表
     * @param sessionTimeout Session超时时间
     */
    public void createConnection(String connectAddr, int sessionTimeout) {
        this.releaseConnection();
        try {
            zk = new ZooKeeper(connectAddr, sessionTimeout, this);
            System.out.println(LOG_PREFIX_OF_MAIN + "开始连接ZK服务器");
            connectedSemaphore.await();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 关闭ZK连接
     */
    public void releaseConnection() {
        if (this.zk != null) {
            try {
                this.zk.close();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 创建节点
     * @param path 节点路径
     * @param data 数据内容
     * @return
     */
    public boolean createPath(String path, String data) {
        try {
            //设置监控(由于zookeeper的监控都是一次性的所以 每次必须设置监控)
            this.zk.exists(path, true);
            System.out.println(LOG_PREFIX_OF_MAIN + "节点创建成功, Path: " +
                    this.zk.create(	/**路径*/
                            path,
                            /**数据*/
                            data.getBytes(),
                            /**所有可见*/
                            ZooDefs.Ids.OPEN_ACL_UNSAFE,
                            /**永久存储*/
                            CreateMode.PERSISTENT ) +
                    ", content: " + data);
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
        return true;
    }

    /**
     * 读取指定节点数据内容
     * @param path 节点路径
     * @return
     */
    public String readData(String path, boolean needWatch) {
        try {
            return new String(this.zk.getData(path, needWatch, null));
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }
    }

    /**
     * 更新指定节点数据内容
     * @param path 节点路径
     * @param data 数据内容
     * @return
     */
    public boolean writeData(String path, String data) {
        try {
            System.out.println(LOG_PREFIX_OF_MAIN + "更新数据成功，path：" + path + ", stat: " +
                    this.zk.setData(path, data.getBytes(), -1));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    /**
     * 删除指定节点
     *
     * @param path
     *            节点path
     */
    public void deleteNode(String path) {
        try {
            this.zk.delete(path, -1);
            System.out.println(LOG_PREFIX_OF_MAIN + "删除节点成功，path：" + path);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 判断指定节点是否存在
     * @param path 节点路径
     */
    public Stat exists(String path, boolean needWatch) {
        try {
            return this.zk.exists(path, needWatch);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 获取子节点
     * @param path 节点路径
     */
    private List<String> getChildren(String path, boolean needWatch) {
        try {
            return this.zk.getChildren(path, needWatch);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 删除所有节点
     */
    public void deleteAllTestPath() {
        if(this.exists(CHILDREN_PATH, false) != null){
            this.deleteNode(CHILDREN_PATH);
        }
        if(this.exists(PARENT_PATH, false) != null){
            this.deleteNode(PARENT_PATH);
        }
    }

    /**
     * 收到来自Server的Watcher通知后的处理。
     */
    @Override
    public void process(WatchedEvent event) {

        System.out.println("进入 process 。。。。。event = " + event);

        try {
            Thread.sleep(200);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        if (event == null) {
            return;
        }

        // 连接状态
        Watcher.Event.KeeperState keeperState = event.getState();
        // 事件类型
        Watcher.Event.EventType eventType = event.getType();
        // 受影响的path
        String path = event.getPath();

        String logPrefix = "【Watcher-" + this.seq.incrementAndGet() + "】";

        System.out.println(logPrefix + "收到Watcher通知");
        System.out.println(logPrefix + "连接状态:\t" + keeperState.toString());
        System.out.println(logPrefix + "事件类型:\t" + eventType.toString());

        if (Event.KeeperState.SyncConnected == keeperState) {
            // 成功连接上ZK服务器
            if (Event.EventType.None == eventType) {
                System.out.println(logPrefix + "成功连接上ZK服务器");
                connectedSemaphore.countDown();
            }
            //创建节点
             if (Event.EventType.NodeCreated == eventType) {
                System.out.println(logPrefix + "节点创建");
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                this.exists(path, true);
            }
            //更新节点
            else if (Event.EventType.NodeDataChanged == eventType) {
                System.out.println(logPrefix + "节点数据更新");
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(logPrefix + "数据内容: " + this.readData(PARENT_PATH, true));
            }
            //更新子节点
            else if (Event.EventType.NodeChildrenChanged == eventType) {
                System.out.println(logPrefix + "子节点变更");
                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(logPrefix + "子节点列表：" + this.getChildren(PARENT_PATH, true));
            }
            //删除节点
            else if (Event.EventType.NodeDeleted == eventType) {
                System.out.println(logPrefix + "节点 " + path + " 被删除");
            }
        }
        else if (Watcher.Event.KeeperState.Disconnected == keeperState) {
            System.out.println(logPrefix + "与ZK服务器断开连接");
        }
        else if (Watcher.Event.KeeperState.AuthFailed == keeperState) {
            System.out.println(logPrefix + "权限检查失败");
        }
        else if (Watcher.Event.KeeperState.Expired == keeperState) {
            System.out.println(logPrefix + "会话失效");
        }

        System.out.println("--------------------------------------------");

    }


    public static void main(String[] args) throws Exception {

        //建立watcher
        ZooKeeperWatcher zkWatch = new ZooKeeperWatcher();
        //创建连接
        zkWatch.createConnection(CONNECTION_ADDR, SESSION_TIMEOUT);
        //System.out.println(zkWatch.zk.toString());

        Thread.sleep(1000);

        // 清理节点
        zkWatch.deleteAllTestPath();



        if (zkWatch.createPath(PARENT_PATH, System.currentTimeMillis() + "")) {



            // 读取数据，在操作节点数据之前先调用zookeeper的getData()方法是为了可以watch到对节点的操作。watch是一次性的，
            // 也就是说，如果第二次又重新调用了setData()方法，在此之前需要重新调用一次。
             System.out.println("---------------------- read parent ----------------------------");

          //  zkWatch.readData(PARENT_PATH, true);
            // 更新数据
           zkWatch.writeData(PARENT_PATH, System.currentTimeMillis() + "");


            /** 读取子节点，设置对子节点变化的watch，如果不写该方法，则在创建子节点是只会输出NodeCreated，而不会输出NodeChildrenChanged，
             也就是说创建子节点时没有watch。
             如果是递归的创建子节点，如path="/p/c1/c2"的话，getChildren(PARENT_PATH, ture)只会在创建c1时watch，输出c1的NodeChildrenChanged，
             而不会输出创建c2时的NodeChildrenChanged，如果watch到c2的NodeChildrenChanged，则需要再调用一次getChildren(String path, true)方法，
             其中path="/p/c1"
             */
            System.out.println("---------------------- read children path ----------------------------");
            zkWatch.getChildren(PARENT_PATH, true);


           Thread.sleep(1000);

            // 创建子节点，同理如果想要watch到NodeChildrenChanged状态，需要调用getChildren(CHILDREN_PATH, true)
            zkWatch.createPath(CHILDREN_PATH, System.currentTimeMillis() + "");

            Thread.sleep(1000);

            zkWatch.readData(CHILDREN_PATH, true);
            zkWatch.writeData(CHILDREN_PATH, System.currentTimeMillis() + "");
        }

        Thread.sleep(20000);
        // 清理节点
        zkWatch.deleteAllTestPath();
        Thread.sleep(1000);
        zkWatch.releaseConnection();
    }

}
